JP2006022829A - Eccentric swing type gear device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an eccentric swing type gear device enabling an increase in the degree of design by reducing an axial dimension while preventing pins forming the internal teeth of an internal gear from being tilted or falling down and an increase in machinability and assemblability. <P>SOLUTION: This eccentric swing type gear device 1 comprises the internal gear 14 in which a large number of pins 17 rotatably held on the inner periphery thereof are used as internal teeth, an external gear 13 having external teeth 13c disposed on the inside of the internal gear 14 and meshing with the pins (internal teeth) 17, a crankshaft engaged with the external gear 13 and eccentrically swinging the external gear, and a support body 2 rotatably supporting the crankshaft. A pin retaining member 18 allowing its outer peripheral surface to come into contact with the outer peripheral surfaces of the pins 17 of the internal gear 14 is disposed between a main bearing (pin restricting member) 15 and the end face of the external gear 13. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an eccentric oscillating gear device provided in a drive unit of an industrial robot or the like.

  For example, an eccentric oscillating gear device is provided in a drive unit of an industrial robot, a machine tool, or the like. This gear device includes an internal gear having a large number of pins that are rotatably held on the inner periphery, and an internal gear. An external gear having an external tooth that is arranged inside the internal gear and meshes with the internal gear, a crankshaft that engages with the external gear and eccentrically swings the external gear, and the crankshaft is freely rotatable It is comprised including the support body supported by.

  By the way, in this type of eccentric oscillating gear device, since all the pins of the internal gear are in contact with the external teeth of the external gear, the respective pins and the external teeth are in continuous rolling contact during operation. . For this reason, each pin is forced to rotate continuously, and there is a possibility that seizure or the like of the pin may occur due to frictional heat due to the rotation.

  Then, as shown in FIG.7 and FIG.8 (C section enlarged detail drawing of FIG. 7), the proposal which cuts the tooth-tip of the external tooth 113c of the external gear 113 is made (refer patent document 1). According to this, since all the pins 117 are not forcibly rotated due to the relationship with the tooth tips of the external teeth 113c, the occurrence of seizure of the pins 117 due to frictional heat can be prevented.

  However, as shown in FIG. 7, the external teeth 113c are disengaged from the pins 117 on the side opposite to the eccentric direction of the external gear 113 (upward in the illustrated example) by 180 ° (downward in the illustrated example). There is a problem that the pin 117 is idle and the pin 117 tilts or falls off. When the pin 117 is inclined or dropped in this manner, the external teeth 113c bite into the pin 117 and noise is generated, or the pin groove 114a (see FIG. 8) of the internal gear 114 is deformed, which is the worst case. In this case, the gear device is locked.

  Therefore, as shown in FIG. 9, a proposal has been made that a pin pressing member 218 is interposed between the main bearing 215 and the end surface of the pin 217, and the pin 217 is restrained by the pin pressing member 218 to suppress its inclination. (See Patent Document 2).

Japanese Patent Laid-Open No. 2-261944 Japanese Patent Publication No. 4-044134

  However, since the pin pressing member 218 shown in FIG. 9 is interposed between the end surface of the pin 217 and the end surface of the main bearing 215 (outer ring 215a), the dimension in the axial direction is increased by the illustrated dimension (Δx × 2). As a result, the degree of freedom of design is limited, and the preload of the main bearing 215 is affected by the pin pressing member 218, so that the illustrated dimension Δx is required to be managed, resulting in poor workability and assembly workability. .

  Further, since the pin pressing member 218 affects the preload of the main bearing, the surface of the pin pressing member 218 that contacts the outer ring 215a, the surface that contacts the end surface of the pin 217, and the surface that slides on the external gear 213. It is necessary to perform a polishing process on this, which complicates the process.

  Further, since the pin pressing member 218 is sandwiched between the end surface of the pin 217 and the end surface of the main bearing 215, the pin pressing member 218 is scraped when the external gear 213 is swung by the rotation of a crankshaft (not shown). There was a problem that the gear device was damaged at an early stage.

  The present invention has been made in view of the above problems, and the object of the present invention is to shorten the axial dimension and increase the degree of design freedom while preventing the inclination and dropping of the pins constituting the internal teeth of the internal gear. In addition, an object of the present invention is to provide an eccentric oscillating gear device capable of improving workability and assembly workability.

  In order to achieve the above object, an invention according to claim 1 is directed to an internal gear having a large number of pins rotatably held on an inner periphery, and an internal gear disposed inside the internal gear. In an eccentric oscillating gear device comprising an external gear having external teeth meshing with the external gear, a crankshaft that engages with the external gear and eccentrically swings the external gear, and a support that rotatably supports the crankshaft A pin presser member whose outer peripheral surface is abuttable against the outer peripheral surface of the pin of the internal gear, and is provided at each end of the pin to restrict axial movement of the pin and each of the external gears. It is characterized by being interposed between the end faces.

  According to a second aspect of the present invention, the pin restricting member according to the first aspect is constituted by a bearing that rotatably supports the internal gear on the support.

  According to a third aspect of the present invention, the same number of concave portions as the pins are formed in the outer peripheral portion of the pin pressing member according to the first or second aspect, and the outer peripheral surface of the pin pressing member is fitted to the pins by fitting the concave portions into the pins. It is characterized by being brought into surface contact.

  The invention described in claim 4 is characterized in that a clearance is provided between the pin pressing member according to any one of claims 1 to 3, and the end surfaces of the pin pressing member and the external gear.

  In the invention according to claim 5, a step portion having a large and small diameter is formed on the outer peripheral surface of the pin pressing member according to any one of claims 1 to 4, the large diameter portion is brought into contact with the pin, and the small diameter portion is The pin regulating member is brought into contact with the pin regulating member.

  According to the first aspect of the present invention, since no member is interposed between the end face of the pin and the end face of the pin restricting member, it is possible to shorten the axial length of the gear device by reducing the distance between the both end faces. This increases the degree of design freedom. Moreover, since the pin pressing member also functions to restrict the axial position of the external gear, the axial positioning member of the external gear can be omitted.

  According to the invention described in claim 2, since the bearing for rotatably supporting the internal gear also serves as a pin restricting member, there is no need to separately provide a pin restricting member, and the number of parts can be reduced and the structure can be simplified. Can do.

  According to the third aspect of the present invention, the concave portion formed on the outer peripheral portion of the pin pressing member is fitted to the pin so that the pin is held by the concave portion, so that the inclination and dropping of the pin are reliably prevented. High operational stability is ensured for the device.

  According to the fourth aspect of the present invention, since the clearance is provided between the end surfaces of the pin pressing member, the pin regulating member, and the external gear, it is not necessary to manage the dimensions in the axial direction.

  According to the fifth aspect of the present invention, the large diameter portion of the step portion formed on the outer peripheral surface of the pin pressing member is in contact with the pin and the small diameter portion is in contact with the pin restricting member. Can be positioned with respect to the pin restricting member, the pin can be easily incorporated, and the pin can be reliably prevented from falling off.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
1 is a side sectional view of an eccentric oscillating gear device according to Embodiment 1 of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. FIG. 4 is an enlarged detailed view of a portion B in FIG. 2.

  In the eccentric oscillating gear device (hereinafter, simply referred to as “gear device”) 1 shown in FIGS. 1 and 2, 2 is a support as a fixing member, and a central hole 3 is formed at the center thereof. . And this support body 2 is comprised by the base disc 4 and the end plate 5, and the end plate 5 is the plurality (in the example of illustration, three: refer FIG. 2) formed integrally with the base disc 4. As shown in FIG. ) And is fastened to the base disc 4 by fastening pins and fastening bolts 6 (not shown).

  A plurality (three in the illustrated example: see FIG. 2) of crankshafts 9 are provided on the outer periphery of the central hole 3 of the support 2 alternately and equally with the column portions 4a. 9 is rotatably supported by the support body 2 via a pair of roller bearings 10. Two eccentric bodies 9a and 9b whose phases are shifted from each other by 180 ° are integrally formed at the central portion of each crankshaft 9 in the axial direction. These eccentric bodies 9a and 9b are respectively needle bearings 12. The two external gears 13 are engaged with each other.

  Further, an input shaft 7 attached to a drive source such as a motor is rotatably inserted and supported in the central hole 3 of the support 2. An input gear 8 is engraved at the end of the input shaft 7. Has been. A transmission gear 11 is attached to one end of each crankshaft 9, and the transmission gear 11 meshes with the input gear 8 formed on the input shaft 7. Therefore, the crankshaft 9 and the input shaft 7 are connected to each other via the input gear 8 and the transmission gear 11, and when a drive source such as a motor is driven, the rotation of the input shaft 7 is transmitted to the input gear 8. The gear 11 is decelerated by the gear 11 and transmitted to each crankshaft 9, thereby rotating each crankshaft 9 at a predetermined speed.

  Here, the two external gears 13 are interposed between the base disk 4 and the end plate 5 of the support 2, and perform a swinging motion by the rotation of the input shaft 7. Incidentally, external teeth 13c are engraved on the outer periphery of each external gear 13, and although not shown, the external teeth 13c form a trochoidal tooth profile and the tooth tips are cut.

  On the other hand, a cylindrical internal gear 14 is disposed on the outer periphery of the support 2, and the internal gear 14 is rotatably supported by the support 2 via a pair of main bearings 15. Further, an oil seal 16 is provided between the inner peripheral surface of the internal gear 14 and the outer peripheral surface of the base disk 4, and the sealing function of the oil seal 16 allows the lubricant in the gear device 1. The outflow to the outside is prevented, and the entry of dust and the like into the gear device 1 from the outside is prevented. A large number of semicircular pin grooves 14 a are formed on the inner periphery of the internal gear 14, and the internal teeth meshing with the external teeth 13 c of the external gear 13 are formed in each pin groove 14 a. A plurality of cylindrical pins 17 are fitted and held rotatably.

  Here, a characteristic configuration of the present invention will be described.

  When the tip of the external tooth 13c of the external gear 13 is cut as described above, the external tooth 13c is disengaged from the pin 17 on the side opposite to the eccentric direction of the external gear 13 so that the pin 17 is idle. Therefore, the problem that the pin 17 tilts or falls off occurs.

  Therefore, a pair of pin pressing members 18 for preventing the pins 17 from falling off and tilting are provided on the left and right sides. In this embodiment, as shown in detail in FIG. 3, each pin pressing member 18 is connected to the main bearing 15 ( It is interposed between the end face of the outer ring 15a) and the end face of the external gear 13, and no member is interposed between the end face of the pin 17 and the end face of the main bearing 15 (outer ring 15a). In the present embodiment, the main bearing 15 also serves as a pin restricting member that restricts the axial movement of the pin 17, and the outer ring 15 a is arranged on the inner periphery of the internal gear 14, on the end surface of the pin 17. The movement of the pin in the axial direction is restricted. Thus, in this embodiment, since the main bearing 15 also serves as a pin restricting member, the number of parts can be reduced and the structure can be simplified.

  Here, as shown in FIG. 2, each pin presser member 18 is formed in a ring shape, and the outer diameter thereof is set to be substantially the same as the diameter of the inscribed circle of the plurality of pins 17, as shown in FIG. As shown, the outer peripheral surface of the pin pressing member 18 is in line contact with each pin 17. In addition, the outer diameter of each pin pressing member 18 is set to be slightly smaller than the diameter of the inscribed circle of the pin 17, and as shown in FIG. 4 (b), between the outer peripheral surface of the pin pressing member 18 and the pin 17. A minute clearance δ that does not cause the pin 17 to drop off or tilt may be formed.

  Further, minute clearances (not shown) are formed between the end surfaces of the pin pressing member 18, the main bearing 15 (outer ring 15 a), and the external gear 13. Here, the end surface of the pin pressing member 18 on the side in sliding contact with the external gear 13 is polished.

  Thus, in the gear device 1 according to the present embodiment, since the pin 17 is held by the pin presser member 18 even if the tip of the external tooth 13c of the external gear 13 is cut, the external tooth The pin 17 does not tilt or drop off even on the side opposite to the eccentric direction of the gear 13 by 180 °, and the gear device 1 can be stably operated.

  In the gear device 1 according to the present embodiment, since no member is interposed between the end surface of the pin 17 and the end surface of the main bearing 15, the distance between both end surfaces is reduced and the axial length of the gear device 1 is reduced. Can be shortened (for example, it can be shortened by the dimension (Δx × 2) shown in FIG. 8), thereby increasing the degree of freedom in design. In this case, since the pin pressing member 18 also functions to restrict the axial position of the external gear 13, a separate positioning member that determines the axial position of the external gear 13 can be omitted. Conventionally, as a means for restricting the axial direction of the external gear, the inner ring of the main bearing has been processed into a special shape so as to be in contact with the end surface of the external gear. Since it is not necessary to perform any processing on the bearing 15, the design freedom of the gear device 1 can be increased and the cost can be reduced.

  Further, in the present embodiment, the pin pressing member 18 can be formed into a simple ring shape, so that the processing becomes easy. And since the outer periphery of the pin pressing member 18 is in line contact with each pin 17, the frictional force between them is suppressed small, and the heat generation and rotational resistance due to friction are suppressed low.

  As shown in FIG. 4B, if a minute clearance δ is provided between the pin presser member 18 and the pin 17, the pin 17 rotates freely without being constrained by the pin presser member 18. Therefore, the wear is suppressed and the operational stability of the gear device 1 is enhanced.

  Furthermore, in the present embodiment, since minute clearances are provided between the end surfaces of the pin presser member 18 and the main bearing 15 and the external gear 13, axial dimension management is not required, and the pin presser member 18 is used as the main member. The preload of the bearing 15 is not affected, and as a result, workability and assembly workability are improved.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a partial sectional view (similar to FIG. 4) showing the relationship between the pin pressing member and the pin.

  The present embodiment is different from the first embodiment only in the shape of the outer peripheral portion of the pin pressing member 18, and the other configuration is the same as that of the first embodiment.

  That is, in this embodiment, the same number of semicircular recesses 18a as the pins 17 are formed on the outer periphery of the pin pressing member 18, and each recess 18a is fitted to the pins 17 as shown in FIG. Thus, the outer peripheral surface of the pin pressing member 18 is brought into surface contact with the pin 17.

  Thus, according to the present embodiment, the concave portion 18a formed on the outer peripheral portion of the pin pressing member 18 is fitted to the pin 17 so that the pin 17 is held by the concave portion 18a. The gear device 1 is ensured to have high operational stability.

  In addition, in this embodiment, the same effect as that obtained in the first embodiment can be obtained.

  As shown in FIG. 5 (b), if a minute clearance δ is provided between the recess 18 a of the pin pressing member 18 and the pin 17, the pin 17 is free from being restrained by the pin pressing member 18. Since it can rotate, its wear is suppressed and the operational stability of the gear device 1 is further enhanced.

<Embodiment 3>
Next, an embodiment of the present invention will be described with reference to FIG.

  FIG. 6 is a partial cross-sectional view showing the relationship between the pin pressing member and the pin. In this figure, the same elements as those shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted below. To do.

  In the present embodiment, stepped portions having large and small diameters are formed on the outer peripheral surface of the pin pressing member 28, the large diameter portion 28 a is brought into contact with the pin 17, and the small diameter portion 28 b is minutely attached to the outer ring 15 a of the main bearing 15. The contact is made through a clearance.

  Thus, according to the present embodiment, the large diameter portion 28 a of the step portion formed on the outer peripheral surface of the pin presser member 28 reliably prevents the pin 17 from falling off, and the small diameter portion 28 b becomes the main bearing 15. On the other hand, since the pin pressing member 28 is positioned, the pin 17 can be easily incorporated into the pin groove 14a of the internal gear 14 at the time of assembly.

  The application of the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the technical idea of the present invention. For example, in the above embodiment, a gear device in which a plurality of crankshafts are arranged around the input shaft has been described. However, a gear device employing a so-called center crank input system in which the input shaft is a crankshaft is also described. The present invention can be applied. Further, the present invention can be similarly applied to a gear device in which a tooth tip of an external tooth is cut to form a two-tooth differential tooth shape.

  The present invention is applicable to the same kind of gear device used for any other driving device in addition to the eccentric oscillating gear device used for the driving device such as an industrial robot.

It is a sectional side view of the eccentric rocking | swiveling planetary gear apparatus which concerns on Embodiment 1 of this invention. It is the sectional view on the AA line of FIG. It is an expanded sectional side view of the eccentric oscillation planetary gear apparatus principal part (around pin pressing member) which concerns on Embodiment 1 of this invention. It is the B section enlarged detail drawing of FIG. It is a fragmentary sectional view (similar figure to FIG. 4) which shows the relationship between the pin pressing member and pin of the eccentric rocking | fluctuation type gear apparatus which concerns on Embodiment 2 of this invention. It is an expanded sectional side view of the eccentric oscillation planetary gear apparatus principal part (around pin pressing member) which concerns on Embodiment 3 of this invention. It is a sectional side view which shows the meshing state of the external gear and internal gear of the conventional eccentric oscillation type planetary gear apparatus. It is the C section enlarged detail drawing of FIG. It is an expanded sectional side view of the conventional eccentric rocking planetary gear apparatus principal part (around a pin pressing member).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Eccentric oscillation type gear apparatus 2 Support body 4 Base disk 5 End plate 7 Input shaft 9 Crankshaft 13 External gear 13c External gear 14 Internal gear 15 Main bearing 17 Pin 18 Pin presser member 18a Recessed part 28 Pin presser member 28a Large diameter portion of the pin retainer step 28b Small diameter portion of the pin retainer step δ Clearance

Claims (5)

An internal gear having a large number of pins rotatably held on the inner periphery, an external gear having an external tooth disposed inside the internal gear and meshing with the internal gear, and the external gear In an eccentric oscillating gear device comprising a crankshaft that engages with and eccentrically oscillates, and a support that rotatably supports the crankshaft,
A pin holding member whose outer peripheral surface is capable of contacting the outer peripheral surface of the pin of the internal gear; a pin regulating member that is positioned at an end of the pin and restricts axial movement of the pin; and an end surface of the external gear; An eccentric oscillating gear device characterized by being interposed between the two.   2. The eccentric oscillating gear device according to claim 1, wherein the pin restricting member comprises a bearing that rotatably supports the internal gear on the support.   The number of concave portions equal to that of the pin is formed in the outer peripheral portion of the pin pressing member, and the outer peripheral surface of the pin pressing member is brought into surface contact with the pin by fitting the concave portion into the pin. 3. The eccentric oscillating gear device according to 2.   The eccentric oscillating gear device according to any one of claims 1 to 3, wherein a clearance is provided between each end surface of the pin pressing member, the pin regulating member, and the external gear.   5. A step portion having a large and small diameter is formed on an outer peripheral surface of the pin holding member, the large diameter portion is brought into contact with the pin, and the small diameter portion is brought into contact with the pin regulating member. The eccentric rocking | fluctuation type gear apparatus in any one of.

Images